The present disclosure relates to aircraft seat ejection, and more specifically, to an aircraft seat ejection mode selector.
When a pilot activates a seat ejection sequencing system one of two ejection modes are possible, depending on the design and function of the aircraft. High velocity aircraft will employ either a canopy jettison system that may remove the canopy with a rocket motor actuator and eject the pilot into clear space, or a canopy fracturing system that breaks the canopy using energetic materials while ejecting the pilot through it with a feature built into the ejection seat. This latter is the faster ejection sequence between the two systems.
A canopy fracturing system may be the least preferred method of the two systems for high velocity aircraft because of risk of injury to the pilot by canopy fragments moving in the wind stream. A canopy fracturing system can consist of a detonating cord that fractures the canopy transparency into small pieces or it can be a detonating cord that cuts or severs the canopy into larger pieces. Canopy fracturing systems may be installed in aircraft that fly in conditions where it may not be possible to jettison the canopy in advance of ejecting the seat because of the time necessary to actuate the rocket motors of the canopy jettison system to perform the canopy removal. For example, in cases where the aircraft is close to the ground (in vertical takeoff aircraft, for example), the time available for safe ejection may be minimal, and the extra 2/10- 3/10 seconds needed to jettison the canopy may exceed the time available to eject the pilot free of the aircraft.
Current ejection systems may not allow the pilot to eject using either the canopy jettison method or the canopy fracturing method because conventional ejection systems do not include both ejection modes combined into a single system. Moreover, conventional systems do not operate in both slow and low flight paths and high altitude and high speed flight paths, to determine the optimal ejection mode based on dynamic flight characteristics such as altitude, airspeed, etc., and configure the ejection system accordingly.